I would render the rooms once, with all the lights on (With cameraClsMode cam,True,True set).
Then render each character individually, with only the light that's in the same room as he is (using CameraClsMode cam,False,False). That way you're still only rendering everything once.
Then render each character individually, with only the light that's in the same room as he is (using CameraClsMode cam,False,False). That way you're still only rendering everything once.